Bananas are harvested from trees in tropical growing regions such as Central and South America. Bananas to be exported are picked green, shipped to distribution centers in consuming regions, and delivered to retail stores in a state of ripeness appropriate for retail sale. Conventionally, growers pack bananas in covered, corrugated cardboard boxes containing about 40 pounds of bananas per box.
The industry-standard method for packaging bananas for shipment to North American retailers has been to pack in corrugated cardboard boxes that have been tailored to this application. Corrugated boxes for bananas are of a 2-piece construction with outside dimensions of about 19.7″ (50 cm) in length×15.75″ (40 cm) in width×9.69″ (24.6 cm) in height. The 2-piece boxes include a bottom and a top cover that telescopes the full height of the bottom to contribute to stacking strength due to the resultant double-wall construction. Corrugated boxes weigh approximately 3 lbs. each.
Filled boxes are placed on pallets in eight layers, each layer including 5 or 6 boxes. Bananas are refrigerated to between 13.5° and 15° C. (56.3 and 59.0° F.) during transport to suspend the ripening process (“put the bananas to sleep”). This allows bananas to reach grocery stores without being overripe.
Pallets of cooled (“sleeping”) bananas are loaded onto ships for transport from growing regions to consuming regions. Temperature continues to be controlled throughout shipment to distribution centers in the consuming regions. Acceptance testing usually occurs at a distribution center. Upon arrival, bananas on a given pallet are inspected to determine if the shipment will be accepted or rejected. A typical inspection involves sampling bananas in 3-4 boxes on each pallet. The bananas are selected at different layers and sides of the 30-48 box arrangement to determine the quality of bananas and their state of ripeness. When shipping in corrugated boxes, a hole is cut in the selected boxes with a knife. One or more bananas are removed through the hole and inspected. Attributes tested include physical appearance, size, sweetness, and temperature.
Accepted pallets of bananas are moved to a ripening room. There the temperature of the bananas is raised and the bananas are exposed to ethylene gas to restart the ripening process (“waken the bananas”). The ripening process continues in the ripening room for about 3-5 days. After sufficient ripening, the pallets are loaded onto trucks at the distribution center for delivery to retail stores. Bananas are inspected during the ripening process in a manner similar to inspection during acceptance so that ripening conditions can be adjusted if needed.
The current transport process for bananas has several disadvantages. During the inspection process, the cutting of containers may result in direct damage to the bananas from the cutting implement as a container is cut, and indirect damage to the bananas may result from structural weakness caused by the cutting of the boxes, which may result in the crushing of bananas during transportation.
Plastic containers have been produced that are designed to replace cardboard boxes for shipping bananas, although they have achieved only limited commercial success. Plastic containers have included re-closable access doors with a hinge at a bottom end and a latch at the top end; however, they have been relatively heavy and had stiff construction. Stiff RPCs with 4 walls and a base are designed to handle stacking loads transferred through the walls and base of containers to the pallet with a safety margin to achieve many years of life. The stiff nature of the RPC has exacerbated packing damage associated with transporting the requisite quantity of bananas.
One proposed plastic container, described in published PCT Application WO2015134067, has a light weight construction giving the box a relatively high flexibility that is similar to corrugated cardboard boxes.
To achieve the reduced weight, the thicknesses of walls have been reduced, and rigidizing features such as ribs in the walls have been reduced in number and in thickness, and positioned to result in increased flexibility of the walls.
While such design choices address concerns such as container weight and damage to fruit, they present challenges in maintaining sufficient integrity of the erected boxes.